About 10 percent of young leukemia patients of East Asian ancestry inherit a gene variation that is associated with reduced tolerance of a drug that is indispensable for curing acute lymphoblastic leukemia (ALL), the most ...

(HealthDay)—For men, income, but not self-identified race/ethnicity or genetic ancestry, is associated with annualized percentage changes in bone mineral density (BMD), according to a study published in ...

Native American ancestry is associated with a lower asthma risk, but African ancestry is associated with a higher risk, according to the largest-ever study of how genetic variation influences asthma risk in Latinos, in whom ...

One of the goals of genome sequencing is to identify genetic mutations associated with increased susceptibility to disease. Yet by and large these discoveries have been made in people of European or Asian ...

New research led by the University of Southern California (USC) Eye Institute, part of Keck Medicine of USC, shows for the first time that Native American ancestry is a significant risk factor for vision-threatening diabetic ...

In the most comprehensive genetic study of the Mexican population to date, researchers from UC San Francisco and Stanford University, along with Mexico's National Institute of Genomic Medicine (INMEGEN), ...

Circumcision is performed for various reasons, including those that are based on religion, aesthetics, or health. New research indicates that the procedure may help prevent prostate cancer in some men. The findings, which ...

(Medical Xpress)—Research led by a University of Cincinnati (UC) neurologist has identified and replicated a genomic susceptibility locus for intracerebral hemorrhage, raising the possibility of targeting a new risk factor ...

(Medical Xpress)—Ancestral background has much to do with our likelihood of developing or staving off disease. But separating the associations between who we are and where we come from, and genetic variations ...

A study from North Carolina State University finds that data from CT scans can be incorporated into a growing forensic database to help determine the ancestry and sex of unidentified remains. The finding ...

Europeans fall prey to skin cancer because of their lighter skin, while Africans' dark skin protects them. But East Asians, whose skin colour resembles that of Europeans, are similar to Africans in their ...

All instances of a gene mutation that contributes to light skin color in Europeans came from the same chromosome of one person who most likely lived at least 10,000 years ago, according to Penn State College of Medicine researchers.

A genomewide association study (GWAS) has revealed two specific variations in the NFIB gene that may identify which children and adolescents with osteosarcoma have metastatic disease or are at high risk for metastasis, according ...

Ancestor

An ancestor is a parent or (recursively) the parent of an ancestor (i.e., a grandparent, great-grandparent, great-great-grandparent, and so forth).

Two individuals have a genetic relationship if one is the ancestor of the other, or if they share a common ancestor. In evolutionary theory, species which share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer.

Assuming that all of an individual's ancestors are otherwise unrelated to each other, that individual has 2n ancestors in the nth generation before him and a total of about 2g+1 ancestors in the g generations before him. In practice, however, it is clear that the vast majority of ancestors of humans (and indeed any other species) are multiply related (see Pedigree collapse). Consider n = 40: the human species is more than 40 generations old, yet the number 240, approximately 1012 or one trillion, dwarfs the number of humans that have ever lived.

Ignoring the possibility of other inter-relationships (even distant ones) among ancestors, an individual has a total of 2046 ancestors up to the 10th generation, 1024 of which are 10th generation ancestors. With the same assumption, any given person has over a billion 30th generation ancestors (who lived roughly 1000 years ago) and this theoretical number increases past the estimated total population of the world in around AD 1000. (All of these ancestors will have contributed to one's autosomal DNA is concerned: this excludes Y-chromosomal DNA and mitochondrial DNA.)

Some cultures confer reverence to ancestors, both living and dead; in contrast, some more youth-oriented cultural contexts display less veneration of elders. In other cultural contexts, some people seek providence from their deceased ancestors; this practice is sometimes known as ancestor worship or, more accurately, ancestor veneration.